[inflagranti]

That's an extremely limited and dare I say outdated view of what constitutes a friend. One of my best friends I only see irregularly once a year at best, sometimes not for years, yet we always get on great when we see each other. That to me is a great friendship, that you know you'll always get along. I don't think it's your place to decide who someone views as a friend and how their relationship should look like.

OP clearly states he met the person online and they communicate online and that might involve irregular but deep, friendly exchanges and meeting up once in a while. I.e. exactly a kind of communication Facebook is supposed to facilitate, yet it completely failed him here which is absolutely valid to criticize and call out.